Lecture 10

src/main/java/it/unimi/di/prog2/e10/BoundedIntQueue.java

@@ -0,0 +1,67 @@
+/*
+
+Copyright 2024 Massimo Santini
+
+This file is part of "Programmazione 2 @ UniMI" teaching material.
+
+This is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This material is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this file.  If not, see <https://www.gnu.org/licenses/>.
+
+*/
+
+package it.unimi.di.prog2.e10;
+
+/**
+ * A <em>queue</em> is a mutable data structure that provides access to its elements in
+ * first-in/first-out order.
+ *
+ * <p>A <em>bounded</em> queue has an upper bound, established when a queue is created, on the
+ * number of elements that can be stored in the queue.
+ */
+public class BoundedIntQueue {
+
+  // EXERCISE: complete following the specification (with particular attention
+  // to the eventual exceptions) and provide an implementation (including the
+  // equals, hashCode, and toString methods); add methods that are adequate to
+  // the specification.
+
+  // Given the boundedness constraint, it is not allowed to use any Java
+  // Collection Framework class. An array can be used to store the elements in a
+  // circular buffer (see https://www.wikiwand.com/en/articles/Circular_buffer).
+
+  /**
+   * Creates a new bounded queue with the given capacity.
+   *
+   * @param capacity the capacity of the queue.
+   * @throws IllegalArgumentException if {@code capacity} is negative.
+   */
+  public BoundedIntQueue(int capacity) {}
+
+  /**
+   * Adds an element to the queue.
+   *
+   * @param x the element to add.
+   * @throws IllegalStateException if the queue is full.
+   */
+  public void enqueue(int x) {}
+
+  /**
+   * Removes the element at the head of the queue.
+   *
+   * @return the element at the head of the queue.
+   * @throws IllegalStateException if the queue is empty.
+   */
+  public int dequeue() {
+    return 0;
+  }
+}

src/main/java/it/unimi/di/prog2/e10/BoundedIntQueueClient.java

@@ -0,0 +1,55 @@
+/*
+
+Copyright 2024 Massimo Santini
+
+This file is part of "Programmazione 2 @ UniMI" teaching material.
+
+This is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This material is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this file.  If not, see <https://www.gnu.org/licenses/>.
+
+*/
+
+package it.unimi.di.prog2.e10;
+
+/** A class to exercise a {@link BoundedIntQueue}. */
+public class BoundedIntQueueClient {
+
+  /** . */
+  private BoundedIntQueueClient() {}
+
+  /**
+   * Tests some methods of {@link BoundedIntQueue}.
+   *
+   * <p>Reads a list of integers from the standard input; if a positive number is read, it is added
+   * to a bounded queue of size 10; if a negative number is read, it is dequeued and emitted on the
+   * standard output. When the input terminates, the queue is emitted on the standard output.
+   *
+   * @param args not used.
+   */
+
+  /* - Uncomment the following after completing the implementation of BoundedIntQueue
+
+   public static void main(String[] args) {
+    BoundedIntQueue queue = new BoundedIntQueue(10);
+    try (java.util.Scanner s = new java.util.Scanner(System.in)) {
+      while (s.hasNextInt()) {
+        int x = s.nextInt();
+        if (x > 0) queue.enqueue(x);
+        else System.out.println(queue.dequeue());
+      }
+    }
+    System.out.println(queue);
+  }
+
+  */
+}

src/main/java/it/unimi/di/prog2/e10/RationalNumber.java

@@ -0,0 +1,62 @@
+/*
+
+Copyright 2024 Massimo Santini
+
+This file is part of "Programmazione 2 @ UniMI" teaching material.
+
+This is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This material is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this file.  If not, see <https://www.gnu.org/licenses/>.
+
+*/
+
+package it.unimi.di.prog2.e10;
+
+/**
+ * A rational number is an immutable number that can be expressed as the quotient or fraction \( p/q
+ * \) of two {@code int}s, a numerator \( p \) and a non-zero denominator \( q \).
+ */
+public class RationalNumber {
+
+  // EXERCISE: complete following the specification (with particular attention
+  // to the eventual exceptions) and provide an implementation (including the
+  // equals, hashCode, and toString methods); add methods that are adequate to
+  // the specification.
+
+  /**
+   * Creates a new rational number.
+   *
+   * @param numerator the numerator.
+   * @param denominator the denominator.
+   */
+  public RationalNumber(int numerator, int denominator) {}
+
+  /**
+   * Returns the sum of this rational number and another one.
+   *
+   * @param other the other rational number.
+   * @return the sum of this rational number and {@code other}.
+   */
+  public RationalNumber add(RationalNumber other) {
+    return null;
+  }
+
+  /**
+   * Returns the product of this rational number and another one.
+   *
+   * @param other the other rational number.
+   * @return the product of this rational number and {@code other}.
+   */
+  public RationalNumber mul(RationalNumber other) {
+    return null;
+  }
+}

src/main/java/it/unimi/di/prog2/e10/RationalNumberClient.java

@@ -0,0 +1,59 @@
+/*
+
+Copyright 2024 Massimo Santini
+
+This file is part of "Programmazione 2 @ UniMI" teaching material.
+
+This is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This material is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this file.  If not, see <https://www.gnu.org/licenses/>.
+
+*/
+
+package it.unimi.di.prog2.e10;
+
+/** A class to exercise a {@link RationalNumber}. */
+public class RationalNumberClient {
+
+  /** . */
+  private RationalNumberClient() {}
+
+  /**
+   * Tests some methods of {@link BoundedIntQueue}.
+   *
+   * <p>Reads a list of pairs of integers from the standard input, corresponding to the numerator
+   * and the denominator of a sequence of rational numbers \( q_i \). Computes the sequence of
+   * rational numbers given by \( r_0 = 0 \) and \( r_{i+1} = q_i + r_i \cdot q_i \). Then compares
+   * the last computed rational number with the rational number given by the pair of integers given
+   * as command line arguments emitting <samp>true</samp> in the standard output if they are equal,
+   * <samp>false</samp> otherwise.
+   *
+   * @param args the numerator and denominator of the resulting fraction.
+   */
+
+  /* - Uncomment the following after completing the implementation of RationalNumber
+
+  public static void main(String[] args) {
+    RationalNumber expected =
+        new RationalNumber(Integer.parseInt(args[0]), Integer.parseInt(args[1]));
+    RationalNumber result = new RationalNumber(0, 1);
+    try (Scanner sc = new Scanner(System.in)) {
+      while (sc.hasNextInt()) {
+        RationalNumber q = new RationalNumber(sc.nextInt(), sc.nextInt());
+        result = q.add(result.mul(q));
+      }
+    }
+    System.out.println(result.equals(expected));
+  }
+
+  */
+}

src/main/java/it/unimi/di/prog2/e10/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Esercizi relativi alla lezione 10, per maggiori dettagli si veda il <a
+ * href="https://prog2.di.unimi.it/diario">diario del corso</a>.
+ */
+package it.unimi.di.prog2.e10;

src/main/java/it/unimi/di/prog2/h09/PolyClient.java

@@ -46,7 +46,7 @@ public static void main(String[] args) {
         Poly term = Poly.monomialWithCoeffAndDegree(s.nextInt(), s.nextInt());
         result = result.mul(term);
       }
-      for (int d = 0; d <= result.degree(); d++) System.out.println(result.coeff(d) + " " + d);
     }
+    for (int d = 0; d <= result.degree(); d++) System.out.println(result.coeff(d) + " " + d);
   }
 }